Communicating thermostats and communicating HVAC equipment generally refer to HVAC equipment that exchange information and control signals using modern communications protocols. The increased flexibility of communicating systems provides several advantages. For example, communicating equipment may be automatically identified, including identification of available capacity settings and/or the number of stages for the equipment. A communicating thermostat may then use this information and the flexibility of the communications protocol to issue control signals corresponding to specific capacity settings to the equipment. Although the use of such protocols provides increased flexibility in the type and amount of data possible to be exchanged between communicating thermostats and communicating HVAC equipment, there are significant tradeoffs. First, communicating thermostats and HVAC equipment are generally more expensive than their non-communicating counterparts, making communicating systems cost prohibitive for many consumers. Second, communicating systems are generally inoperable with non-communicating equipment, older equipment, and equipment from different manufacturers. As a result, consumer choice is extremely limited regarding equipment to be used in a communicating system. Moreover, this lack of interoperability limits the ability of a consumer to retrofit or upgrade a system without a relatively complete replacement. Finally, while many of the features and capabilities of communicating systems make installation and setup much easier, many of these features have limited use for the end user.
In contrast, legacy thermostats and HVAC equipment generally rely on simpler control signals, such as on/off-type signals (typically 24 VAC signals), for communication and control. As a result, interoperability is generally less of a concern in HVAC systems implementing only legacy equipment, and consumers are given more flexibility in installing equipment that better suit their specific needs and budget. As used herein, the term “legacy” refers to equipment that has the ability to connect with a thermostat that sends 24 VAC on/off signals.
In light of the above, there is a need for a system that provides the improved degree of control afforded by a communicating system while allowing a broad range of thermostats and other HVAC equipment to be used within the system. Preferably, the system would allow for both communicating and non-communicating legacy equipment and the device discovery and configuration processes would occur using several methods alone or in combination and may include reading or retrieving information provided by an installer, customer, or other user; reading or retrieving information available in a remote database; reading or retrieving information directly from the HVAC equipment; or learning the properties of the HVAC equipment using a trial and error approach.